Melting point of old solder

[Ray K]

I tried disassembling a 1/2" copper elbow from water pipes, using a propane torch that comes in a $20 Worthington plumbing kit from Lowe's. The solder wouldn't melt. I'm wondering if the solder used around 1969 had a much higher melting point than what's used today. I did keep the tip of the blue flame on the elbow, and I tried heating around all sides of the elbow.

The house is part of a development of 600 or so houses, so I doubt the builder authorized some expensive, high temperature silver solder.

All the water was drained from the pipe, and the end of the pipe that supplies cold water to the utility tub faucet was disconnected from the faucet. The pipe from the faucet to the elbow is 4". The other pipe into the elbow is about 6 feet long.

Thanks,

Ray

[Lefty]

The common old solder, which was 50/50 melted around 375 degrees F. The silver-safe solder we use now melt at higher temperatures, not lower than that. However, some plumbers, especially the boiler men, used 95/5 back in the day, and some still do. It melts at higher temperature as well. I'm guessing your problem is that there is some water in the pipe yet though. It only takes a few drops for the steam to cause a rapid cooling effect.

[Don & Lucille]

[Doug Miller]

[Doug Miller]

No. Actually, the reverse is true: the no-lead formulas in use today have a higher melting point than any of the leaded solders that were in common use in the 60s.

[...]

I suspect otherwise...

And I'll bet that 6 feet is full of water.

[Heathcliff]

As others have said, most likely the solder used in 1969 had a lower melting point than the stuff you can get now. There may be a problem with residual water in the pipe. But also, I have had it happen where I heated the pipe, melted the solder, then for some reason it still won't easily come apart, it is stuck/hung up on something. The finally I yank on it hard enough and it comes apart, splashing hot solder around. Ouch!

So if you are sure the water is out, try heating and disassembling with firm, controlled pressure. If that doesn't work, the next best option may be to just cut the pipe (pipe cutter or hacksaw) and and repair it later with a straight connector. Is there something wrong with the elbow, or do you just need to get the pipe loose? The cut/ repair option may in fact be easier than trying to disassemble the elbow. -- H

[Steve Barker]

Just cut the old out. Then you'll see how much water was really left in there absorbing all your heat. Then when you get it drained for real, you can proceed with the repair.

[jeff_wisnia]

Quite likely the solder and the copper over time have created intermetallic compounds which have a significantly higher melting temperature than the original solder.

That's why you sometimes hear a squeeking noise like a dry door hinge when you've heated an elbowed joint plenty hot enough and still have to twist it back and forth while pulling on it to work it off a pipe end.

Jeff

[Doug Miller]

You're thinking of 60/40. The melting point of 50/50 is 421 deg F.

[Stormin Mormon]

Well, you never know. Solder a pipe together, and leave it for 30 or 40 years. Very possible.

[RicodJour]

Let's back up here a bit. What are you tying to do? People are addressing this as a matter of technique, but another approach might work better for you.

Check out Sharkbite fittings from Cash Acme. You cut the copper, deburr it and then simply press the fitting onto the copper pipe. Figure six or eight bucks per fitting and you won't need a torch at all.

R

[ransley]

MAP gas makes life easy.

[Don Young]

You have received quite a bit of good advice. Jeff mentioned a very common problem. Copper actually slowly dissolves in molten solder and as it does it raises the melting point of the alloy. Higher temperatures cause more alloying and still higher melting points. The best way to unsolder pipe is to heat just to the melting point and then quickly jar the pieces apart. Soldered plumbing rarely just slips apart easily and heating it more often does not help. Cutting apart is nearly always easier.

Don Young

[Ed Pawlowski]

Adding flux and solder helps to take a joint apart?

[Ernie Willson]

I believe doing this might increase the heat transfer and make it easier to melt the old solder.

EJ in NJ

[JIMMIE]

Most common problem is holding the torch too close to the work.

Jimmie

[JIMMIE]

I just tried these for the first time. They are great for mods and small projects but could be expensive for plumbing the whole house.

Jimmie

[JIMMIE]

The best torch I have used was a craft torch my wife got for making glass beads.

Jimmie

[JIMMIE]

Start a nail in a board or clamp it in a vice then heat the nail with your torch until it glows then use different positions on the flame to see where the hotest and coolest portions of the flame are. Play around with it a few minutes and you will lean to control the temperature of the torch.

Jimmie

[Ray K]

I just looked at the video.

The system is awesome. Later this week when I have the plumbing inspector here to check my new water heater, I'll ask him about Shardbite.

Thanks for the lead.

Ray